How to Waterproof Granite

Always check the absorbency of your granite before applying a waterproofing agent. If the granite in your home absorbs water or oil easily, using a waterproofing treatment can make upkeep significantly easier. While no product can offer absolute protection against stains, a good waterproofing agent gives you enough time to clean up spills before they seep into the stone. Remember, waterproofing does not affect the shine of the stone; polishing determines that.

Check if your granite needs waterproofing. While many types of granite don’t require waterproofing, it’s still common practice to apply a sealant. To test the stone’s surface, drop a few water droplets or place a wet paper towel on a hidden part of the countertop for 10-15 minutes. If the water soaks in and darkens the stone, proceed to the next step of waterproofing. If the water remains on the surface, your granite is resistant to staining, and waterproofing isn’t necessary.

• If your granite will come into contact with oil-based products, test it with a few drops of mineral oil. Apply a waterproofing treatment if either test causes the stone to darken.
• If water doesn’t absorb, skip the waterproofing. The agent needs to penetrate the stone to be effective, and it will simply pool if not absorbed.

Avoid spilling lemon juice on the countertop. The “lemon juice” test is often mentioned in online articles, but according to the Natural Stone Research Institute, acidic products like vinegar and lemon juice can corrode the surface of the stone. Granite is particularly sensitive to both acidic and alkaline substances, and products such as lemon juice and vinegar can damage the surface and the adhesive layer underneath.

Choose a waterproofing solution for natural stone. Only use products specifically designed for natural stone, ideally for granite. The waterproofing agent will penetrate the surface, reducing the stone's absorbency. It will effectively protect the surface from stains over an extended period. These guidelines are sufficient to safely protect your countertop, but you can dive deeper into the documentation if you're interested:

• For the best results, select a carbon-based waterproofing agent. Look for a product labeled with “fluorocarbon aliphatic resin.” This option can protect your countertop for years, but it is the most expensive.
• The next best option is a product containing “siloxane” or “silane,” though it offers lesser protection against oil.
• Avoid using silicone-based or linseed oil-based waterproofing agents. They are the least durable and need reapplication every eight months, sometimes even causing discoloration.
• Some waterproofing chemicals are water-based or solvent-based. Experts disagree on the effectiveness of both; however, water-based agents are easier to apply and more environmentally friendly.
• After applying the waterproofing agent, consider using cleaning solutions with ioSeal Protectants, as they help enhance and maintain waterproofing effectiveness without leaving residue on the surface.

Read the instructions on the label. There are many different types of waterproofing agents, so it's best to follow the instructions provided with the product. The method outlined here goes into more detail than the label instructions, but always follow the label’s directions if there is a conflict.

Clean the granite countertop. Wipe the surface with water and dish soap or a specialized stone cleaner like Tenax, then dry with a soft cloth (use a lint-free cloth). Apply a degreaser, then wipe with ethanol alcohol. Allow 24 hours for the granite to dry completely and for the color to return to its original shade, or wait 8 hours if the work area is windy.

• If the countertop is newly installed and other construction work is still ongoing in the kitchen, it’s best to wait until the other tasks are finished. Dust from ongoing work can affect the waterproofing agent’s effectiveness.

Wear gloves and ventilate the workspace. Solvent-based sealants may release unpleasant or harmful fumes, so it's essential to open windows and wear gloves. Don't worry; the sealant won't leave any toxic chemicals in your kitchen.

Test in a small area first. Choose a small, unobtrusive corner on the countertop, perhaps near where the microwave or other appliances are placed. Follow the steps on a small area first to ensure the sealant is compatible with the granite. If it leaves a cloudy residue or discoloration, look for a different product.

• Although the advice in this preparation section will prevent most issues, granite comes in so many varieties that it can be hard to completely avoid the risk of damage.

Apply the sealant. Evenly spray the sealant onto the surface, or use a clean, lint-free cloth or brush if the product isn’t in a spray bottle. The entire surface will become damp but not soaked.

Allow the sealant to soak into the stone. Check the instructions for the waiting time, as waiting too long may cause discoloration of the granite. Typically, the sealant needs about 20 minutes to absorb, but always refer to the label for specific guidance.

Apply a second coat if necessary. If the label advises a second layer, this is typically done when the first coat is nearly dry. Apply the second coat just like the first one.

Wipe off excess sealant. After waiting for twenty minutes or as per the product's instructions, use a clean cloth to remove any leftover sealant. Leaving excess sealant can create an unsightly cloudy layer on the surface.

Leave the countertop undisturbed for 48 hours. This time frame depends on the product, but the sealant needs some time to cure and activate. While some products require only one or two hours, it’s advisable to avoid washing the countertop for the first 48 hours after applying the sealant.

• The longevity of the protective layer can range from one to fifteen years depending on the sealant's quality and the granite color. You can test with water to determine if reapplication is needed or reseal anytime the stone darkens after water exposure. Always test with water before applying any sealant.
• If the sealant leaves a cloudy residue on the stone, try applying more of the same product to dissolve the haze and wipe it away quickly. If this doesn’t work, use a mild abrasive cleaner to clean the surface.

• No sealant can provide absolute protection against stains. Sealants are designed to slow down the absorption of liquids, giving you more time to clean up. The best sealant might not be ideal for granite countertops, as natural stone requires 'pores' to prevent cracking and other damage.
• Sealants will not protect against corrosion caused by chemical reactions between natural stone and acidic liquids. You’ll need a corrosion-removing product to address this type of damage.

• Clean white cloth
• High-quality sealant